Forget Mars: Why the Next Great Age of Discovery is Under the Ocean

I was watching a live stream of the Artemis rocket launch this week, and it is hard not to be moved by it. The sheer scale of the machine, the thunderous noise, the agonizingly slow rise off the launchpad, and then the incredible speed it builds as it punches through the atmosphere. There is something about watching a launch that reaches into a very old part of the brain—the part that has always wanted to go somewhere new just to find out what is there.

It made me stop and think about what "exploration" actually means. NASA is spending billions of dollars and decades of engineering to send a small number of humans back to a place we have already been. It is extraordinary work, and I do not diminish it for a second. But while that is happening, the largest and least explored environment on Earth sits right here. It covers more than seventy percent of the planet's surface, yet we have mapped less than a quarter of it in any real detail. A significant portion of what remains unknown is accessible to any recreational diver with the skills and the mindset to approach it seriously.

This article is not about technical diving, saturation diving, or remotely operated vehicles. It is about what exploration actually means for the rest of us—and how you can approach your diving with the mindset of a genuine explorer rather than a tourist moving through someone else's landscape.

What is exploration?

I work in adventure travel for my day job, and the most overused word in the industry is "explore." People say they want to "explore" a new destination, but in reality, that destination is only new to them. They are often just following the same paths millions of people have trodden before; the modern tourist trail couldn’t be further from true exploration.

True exploration means you are the first to see something—the first to lay eyes on a place, a wreck, or a reef system. For us as divers, that is a relatively easy thing to achieve—certainly much easier than it is to do on land.

The Myth of the "Mapped" Ocean

People are often surprised to learn how little we actually know about the underwater world. The common assumption is that science has broadly figured it out—it hasn't. New species are discovered regularly in locations that have been dived for decades. The behavior of animals that have been studied for years still produces surprises. Entire reef systems in remote areas remain undocumented, and underwater cave networks extend further every time a diver pushes deeper into them. Wrecks from every era of maritime history sit on the seafloor unidentified—some in remarkably shallow water.

The critical point for recreational divers is that a massive proportion of this unknown territory sits well within standard recreational depth limits. The reef systems, wrecks, caves, cold-water kelp forests, volcanic vents, and seamounts that have never been seriously photographed are not all hidden in the abyss; many are within forty meters (131 feet) of the surface.

The true barrier to exploration isn't depth—it's attitude. Most divers follow the same routes, dive the same sites, and look at the same subjects. The diver willing to go a little further, look a little harder, and prepare a little more thoroughly will find things most people never see.

This is what makes underwater exploration genuinely accessible in a way that space exploration is not. You don’t need to be hand-picked by a government agency or be in the top fraction of a percent of physical fitness. You simply need solid dive skills, keen situational awareness, a willingness to research before you gear up, and the patience to stay present in the water long enough for the environment to reveal itself.

Wrecks: The Democracy of Discovery

Wrecks are among the most democratic forms of underwater exploration. There are hundreds of thousands of them worldwide; while many are well-documented and regularly visited, many more are not. Some sit in waters that have been dived for years without the wreck itself ever being properly explored or identified.

The story that immediately comes to mind when I think of wreck exploration as genuine detective work is that of John Chatterton and Richie Kohler. In the early 1990s, they spent years diving a mystery wreck off the coast of New Jersey. The ship sat at around 70 meters (230 feet)—beyond recreational limits—but the principle of their work applies at any depth. They found an unidentified hull, and rather than simply diving it and moving on, they committed to understanding it: who built it, when, what happened to it, and who was on board. The process took years, involved archival research across multiple countries, and ultimately identified the vessel as the German submarine U-869, lost with all hands in 1945. Their journey, documented in the book Shadow Divers by Robert Kurson, remains one of the most compelling accounts of what wreck exploration truly involves.

Jacques Cousteau brought wreck diving to a global audience when he filmed the SS Thistlegorm in the Red Sea in the 1950s. The Thistlegorm is now one of the most visited wrecks in the world, but when Cousteau found it, the location had been largely forgotten since the ship was sunk by German bombers in 1941. It is a powerful reminder that discovery does not always mean going where no one has ever been; sometimes, it means finding something that has been lost.

For recreational divers, wreck exploration is about developing a real relationship with a site rather than merely ticking it off a list. Learn the history of what you are diving. Understand the context of why it is there. Map sections that have not been properly documented. Photograph details that have not been recorded. Bring that information back and share it. That is exploration—and it happens on wrecks all over the world within recreational depths.

The Inner Space: Caves and Caverns

Cave diving sits at one end of the exploration spectrum in terms of preparation and risk management. It is not for everyone, and I want to be clear: no one should approach it without proper training and certification. However, cave and cavern systems represent some of the most genuinely unknown territory left on Earth. What has been found within them has fundamentally changed our understanding of human prehistory and planetary geology.

Jill Heinerth is one of the most important explorers working in any environment, above or below the water. She has dived inside Antarctic icebergs, explored cave systems across North America and the Caribbean, and led expeditions that mapped some of the most complex underwater passages ever recorded. Her work in the Wakulla Springs cave system in Florida helped establish mapping methods still used today. Heinerth has also been a leading voice on the relationship between cave systems and our freshwater supply, arguing that what happens inside these submerged passages matters enormously to the communities living above them.

In Mexico, the Sistema Sac Actun in the Yucatán Peninsula is the longest underwater cave system ever mapped, spanning more than 370 kilometers (230 miles)—and it is still being extended by divers today. Within its passages, explorers have found the skeletal remains of extinct megafauna and some of the oldest human remains discovered in the Americas. The system tells a story stretching back more than 10,000 years, and parts of it are still being entered for the very first time.

The entry point for most is cavern diving, which stays within the zone of natural light and does not require the same level of training or equipment as full cave certification. Even at this level, the environment is unlike anything in open water. The geometry of the passages, the unique behavior of light, and the startling clarity of the water create a sense of being somewhere very few people have ever been. It is a feeling unlike anything else in recreational diving.

Scientific Exploration

Science and exploration are not separate disciplines underwater. The history of marine science is largely a history of people going somewhere, looking carefully, and bringing back information that changed our understanding of the world. That process has not stopped; it is ongoing, and recreational divers play a larger part in it than most realize.

Sylvia Earle has spent more than six decades arguing that the ocean is not simply a backdrop for human activity, but an environment we depend on completely and understand very poorly. Her career began in the 1960s with scientific dives on reef systems that produced detailed observations of plant and animal communities that had never been properly recorded. She went on to set depth records, lead major research expeditions, and become one of the most effective advocates for marine protected areas in the world. What is striking about her early work is how much of it was conducted at depths any recreational diver could reach—and how significant her findings were simply because nobody had looked carefully enough before.

I have had the opportunity to dive hydrothermal vents in Iceland, and that experience changed how I think about exploration in practical terms. Iceland sits on the Mid-Atlantic Ridge, and in certain areas, the geology is active enough that you can dive in water being heated and chemically altered by volcanic activity below the seafloor. The vent systems I dived are not at extreme depths; they are accessible. Yet, they are also strange and largely undocumented in terms of detailed photographic records, and every dive produces something that feels genuinely new. That feeling is available to any diver willing to visit locations that aren't on the standard "top ten" lists.

Citizen science has also made it possible for recreational divers to contribute directly to scientific understanding in ways that were unavailable a generation ago. Platforms like Reef Check, CoralWatch, and iNaturalist allow divers to record observations that feed into global databases tracking reef health, species distribution, and environmental change. This is not passive participation. When a diver documents a species at a new location or records a behavioral observation that doesn't fit a published pattern, that data matters. The ocean is too vast and complex for the professional scientific community to monitor alone.

Polar and Cold Water Exploration

Cold-water diving remains one of the least explored categories in recreational diving, which is striking given how much of it is accessible. The assumption that interesting diving only happens in warm, tropical water has left a massive portion of the world's oceans underexplored—simply because fewer divers are willing to embrace the cold.

I dive in Iceland. I have been doing it for years, and it still surprises me. Iceland is an island with a population of only 350,000, yet it possesses over 4,800 kilometers (3,000 miles) of coastline. Much of the ocean here can be accessed via simple shore diving, yet almost none of it has been truly explored. The marine life is unlike anything you encounter in the tropics. Furthermore, the geology of diving in an actively volcanic region—where the landscape above and below the waterline is shaped by forces still in motion—gives every dive a "quality of aliveness" that is difficult to describe to those who haven't experienced it.

I have also been fortunate enough to dive both polar regions while working with Blue Green Expeditions. There is a unique thrill in being dropped into the ocean in a place like Greenland or Antarctica and being among the first humans to see what lies beneath. The same is true for ice and iceberg diving; what you see on any given day, no one else will ever see again, as the ice melts and conditions shift by the hour.

Cold-water diving rewards patience and preparation in a way that warm-water diving sometimes does not. The environment is less forgiving of a careless approach to training, equipment, or planning. However, it also produces encounters, images, and experiences that the majority of the diving world has never seen—simply because they haven't been there.

How to Actually Start Thinking Like an Explorer

Exploration is not a level you reach after a certain number of dives; it is a mindset you choose. It is available to you from the moment you possess the skills to dive safely and independently.

The first step is to stop looking only at established dive resorts and the exotic destinations you see in the pages of magazines. Instead, start thinking about what you can access in your own backyard. Wherever you live, there is bound to be unexplored water waiting for you. Even a local diver who goes looking for lost items in a nearby lake has done more true exploring than many seasoned holiday divers.

Research matters more than most recreational divers realize. Before an exploratory dive, take the time to study sea charts and check tides, currents, and local topography to understand exactly what you are getting into. Remember that one of the best ways to begin exploring a location is often with a simple snorkel. This allows you to cover a huge amount of ground and scout an area efficiently before you commit to planning more thorough, equipment-heavy dives.

Exploration doesn't require a rocket or a billion-dollar budget. It requires a curious mind, a bit of homework, and the willingness to look where others have simply passed by. The next time you gear up, don't just go for a dive—go find something new.

The Explorer’s Checklist

Finding the sites that aren’t on the standard itinerary is where the real work begins. Every dive destination has a list of "greatest hits" that operators visit regularly because they are reliable and straightforward. Those sites exist for good reason, but beyond them, there are almost always areas that are dived rarely or not at all. That is where exploration happens.

To find them, you have to look outside the brochure:

• Talk to local fishermen about where they see unusual currents or bottom structures.

• Study historical charts for forgotten landmarks or navigational hazards.

• Ask dive guides about the sites they never get requests to visit.

Once you find something, document it. Whether it’s through photography, video, written notes, or GPS positions, bring that information back and share it. The true value of exploration isn't simply in having been somewhere; it is in what you bring back from the experience and how it adds to our collective understanding of a place.

A Mission for the Rest of Us

The Artemis program will eventually put humans back on the moon, and that matters. But right now, today, you can gear up and enter an environment that covers most of this planet and remains largely unknown.

You can find things that have never been found. You can document places and moments for which no record currently exists. You can contribute to a deeper understanding of the ocean and, in doing so, have a truly unique and memorable experience. The last frontier isn't hundreds of thousands of miles away—it’s right beneath the surface, waiting for you to take the first look.